Circuit board with built-in electronic component and method for manufacturing the same

ABSTRACT

A circuit board with an built-in electronic component according to the present invention includes an insulating layer, a first wiring pattern provided on a first main surface of the insulating layer, a second wiring pattern provided on a second main surface different from the first main surface of the insulating layer, and an electronic component such as a semiconductor chip or the like provided in an internal portion of the insulating layer. The electronic component includes a first external connection terminal formed on a first surface and a second external connection terminal formed on a second surface different from the first surface. The first external connection terminal is connected electrically to the first wiring pattern, and the second external connection terminal is connected electrically to the second wiring pattern.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to circuit boards with built-in electroniccomponents that have electronic components built in, such as activecomponents such as semiconductor devices or the like and passivecomponents such as capacitors or the like, and methods for manufacturingthe same.

2. Related Background Art

Along with a call for higher performance and miniaturization inelectronic equipment in recent years, there has been an even greatercall for higher density and higher performance in semiconductor devices.Moreover, circuit boards that can achieve miniaturization and highdensity also are desired. For this reason, circuit boards with built-inelectronic components have been proposed (for example, see JP2001-332866A) that have at least one electronic component such as an,active component or a passive component embedded internally and areprovided with an inner via through which a wiring pattern and theelectronic components are connected electrically.

FIGS. 23 and 24 are cross-sectional views showing configuration examplesof conventional circuit boards with built-in electronic components. Acircuit board 1001 with built-in electronic components shown in thedrawings is an built-in semiconductor device type circuit board. Thecircuit board 1001 with built-in electronic components shown in FIG. 23has a multi-layer wiring structure with a first wiring pattern 1002formed on one main surface (a first main surface) of one side of aninsulating layer 1005, and a second wiring pattern 1003 formed onanother main surface (a second main surface) of another side of theinsulating layer 1005. The insulating layer 1005 is formed with acomposite material in which an inorganic filler and a thermosettingresin are mixed. The first wiring pattern 1002 and the second wiringpattern 1003, which are positioned on different surfaces of theinsulating layer 1005 from each other, are electrically connected by aninner via 1004 made of an electroconductive resin composition.Semiconductor chips 1006 are embedded inside the insulating layer 1005,and external connection terminals 1007 of the semiconductor chips 1006are connected electrically to the first wiring pattern 1002 viaconnection members 1008 (for example, see JP 2001-332866A).

However, there are structural impediments to increasing packagingdensity in the above-described conventional example and it is difficultto achieve high density. The following is a description of this problem.

In the circuit board 1001 with built-in electronic components shown inFIG. 23, the external connection terminals 1007 of the semiconductorchips 1006 are formed on a surface facing the first wiring pattern 1002,and therefore can be directly connected to the first wiring pattern 1002using the connection members 1008. In contrast to this, a directconnection is not possible when it is necessary to electrically connectthe external connection terminals 1007 to the second wiring pattern1003, which is opposed to a surface on which the external connectionterminals 1007 of the semiconductor chips 1006 are not provided (forexample, when connecting an external connection terminal 1007 a to awiring 1003 a contained in the second wiring pattern 1003), andtherefore a connection must be made via the first wiring pattern 1002and the inner via 1004. In this manner, because it is necessary to useother wiring (the first wiring pattern 1002) and the inner via 1004 whenconnecting the external connection terminal 1007 and the second wiringpattern 1003, the containment rate of wiring is reduced, thus making itdifficult to achieve higher density.

Furthermore, as shown in FIG. 24, with semiconductor chips 1006 in whichexternal connection terminals are provided on a surface of one sideonly, the pitch of the external connection terminals is restricted tothe pitch of the wiring when connecting external connection terminals1007 b through 1007 f to the wirings 1002 b through 1002 f contained inthe wiring pattern 1002. For this reason, regardless of the ability tofurther miniaturize the semiconductor chips 1006, the size of thesemiconductor chips 1006 is restricted due to the above-describedreason, so that there is also the problem of miniaturization beinginhibited.

SUMMARY OF THE INVENTION

A circuit board with an built-in electronic component of the presentinvention includes an insulating layer, a first wiring pattern providedon a first main surface of the insulating layer, a second wiring patternprovided on a second main surface different from the first main surfaceof the insulating layer, and at least one electronic component providedin an internal portion of the insulating layer. The electronic componentcomprises a first external connection terminal formed on a first surfaceand a second external connection terminal formed on a second surfacedifferent from the first surface. The first external connection terminalis connected electrically to the first wiring pattern, and the secondexternal connection terminal is connected electrically to the secondwiring pattern.

A first method for manufacturing a circuit board with an built-inelectronic component of the present invention includes (a) positioningand mounting, on a sheet-form first electroconductive body, anelectronic component including a first external connection terminalformed on a first surface and a second external connection terminalformed on a second surface different from the first surface so as toform an electronic component-mounted structure in which the firstexternal connection terminal and the first electroconductive body areelectrically connected; (b) forming a layered structure by positioningand superposing an uncured sheet-form material formed of a mixtureincluding an inorganic filler and a thermosetting resin, and asheet-form second electroconductive body in this order on the electroniccomponent-mounted structure; (c) pressing the layered structure in alayered direction and heating the same to embed the electronic componentof the electronic component-mounted structure in the sheet-formmaterial, and to connect electrically the second external connectionterminal and the second electroconductive body; and (d) forming a wiringpatterns using the first electroconductive body and the secondelectroconductive body respectively.

A second method for manufacturing a circuit board with an built-inelectronic component includes (a) positioning and mounting, on a firstwiring pattern formed on a support member, an electronic componentincluding a first external connection terminal formed on a first surfaceand a second external connection terminal formed on a second surfacedifferent from the first surface so as to form an electroniccomponent-mounted structure in which the first external connectionterminal and the first wiring pattern are electrically connected; (b)forming a layered structure by positioning and superposing an uncuredsheet-form material formed of a mixture including an inorganic fillerand a thermosetting resin, and a second wiring pattern formed on asupport member in this order on the electronic component-mountedstructure; and (c) pressing the layered structure in a layered directionand heating the same to embed the electronic component of the electroniccomponent-mounted structure in the sheet-form material, and to connectelectrically the second external connection terminal and the secondwiring pattern.

It should be noted that in the first and second methods, the uncuredsheet-form material also includes a sheet-form material that is curedpartially so that the material can be still leaved in a pliablecondition.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a cross-sectional view showing a configuration of a circuitboard with built-in electronic components of a first embodiment of thepresent invention.

FIGS. 2A to 2F are cross-sectional views showing the steps in a firstexample of a method for manufacturing a circuit board with built-inelectronic components of a first embodiment of the present invention.

FIGS. 3A to 3F are cross-sectional views showing the steps in a secondexample of a method for manufacturing a circuit board with built-inelectronic components of a first embodiment of the present invention.

FIGS. 4A to 4F are cross-sectional views showing the steps in a thirdexample of a method for manufacturing a circuit board with built-inelectronic components of a first embodiment of the present invention.

FIG. 5 is a cross-sectional view showing a configuration of a circuitboard with built-in electronic components of a second embodiment of thepresent invention.

FIGS. 6A to 6F are cross-sectional views showing the steps in a methodfor manufacturing a circuit board with built-in electronic components ofa second embodiment of the present invention.

FIG. 7 is a cross-sectional view showing a configuration of a circuitboard with built-in electronic components of a third embodiment of thepresent invention.

FIG. 8 is a cross-sectional view showing a configuration of a circuitboard with built-in electronic components of a fourth embodiment of thepresent invention.

FIGS. 9A to 9F are cross-sectional views showing the steps in a firstexample of a method for manufacturing a circuit board with built-inelectronic components of a fourth embodiment of the present invention.

FIGS. 10A to 10F are cross-sectional views showing the steps in a secondexample of a method for manufacturing a circuit board with built-inelectronic components of a fourth embodiment of the present invention.

FIG. 11 is a cross-sectional view showing a configuration of a circuitboard with built-in electronic components of a fifth embodiment of thepresent invention.

FIGS. 12A to 12E are cross-sectional views showing the steps in a methodfor manufacturing a circuit board with built-in electronic components ofa fifth embodiment of the present invention.

FIG. 13 is a cross-sectional view showing a first configuration exampleof a circuit board with built-in electronic components of a sixthembodiment of the present invention.

FIGS. 14A to 14E are cross-sectional views showing the steps in a methodfor manufacturing a circuit board with built-in electronic components ofa sixth embodiment of the present invention.

FIG. 15 is a cross-sectional view showing a second configuration exampleof a circuit board with built-in electronic components of a sixthembodiment of the present invention.

FIG. 16 is a cross-sectional view showing a third configuration exampleof a circuit board with built-in electronic components of a sixthembodiment of the present invention.

FIG. 17 is a cross-sectional view showing a fourth configuration exampleof a circuit board with built-in electronic components of a sixthembodiment of the present invention.

FIG. 18 is a cross-sectional view showing a configuration example of anelectronic component formed by a plurality of semiconductor chips.

FIGS. 19A and 19B are cross-sectional views showing a configuration of acircuit board with built-in electronic components of a seventhembodiment of the present invention.

FIGS. 20A to 20E are cross-sectional views showing the steps in a methodfor manufacturing a circuit board with built-in electronic components ofa seventh embodiment of the present invention.

FIG. 21 is a cross-sectional view showing a configuration example of acircuit board with built-in electronic components of a fifth embodimentof the present invention.

FIG. 22 is a cross-sectional view showing a configuration of a circuitboard with built-in electronic components of an eighth embodiment of thepresent invention.

FIG. 23 is a cross-sectional view showing a configuration example of aconventional circuit board with built-in electronic components.

FIG. 24 is a cross-sectional view showing another configuration exampleof a conventional circuit board with built-in electronic components.

DETAILED DESCRIPTION OF THE INVENTION

According to a circuit board with built-in electronic components of thepresent invention, the external connection terminals of the electroniccomponents are provided on different surfaces of the electroniccomponents from each other, and therefore the number of surfaces thatcan be used in electrically connecting the external connection terminalswith the wiring patterns in the built-in electronic components isincreased. In this manner, the containment rate of wiring can beincreased, and higher density packaging can be achieved. Moreover, thisalso eases the design rules for the external connection terminals, andcan therefore achieve miniaturization. It should be noted that thecircuit board with built-in electronic components of the presentinvention also includes a configuration in which, for example, when thebuilt-in electronic components are formed with a single surface such asthat of a spherical body, the external connection terminals are providedso that they face different orientations from each other.

In the circuit board with built-in electronic components of the presentinvention, it is preferable that the first surface is a surface facingthe first wiring pattern in the electronic component and that the secondsurface is a surface facing the second wiring pattern in the electroniccomponent. This is because the containment rate of wiring can be madevery high.

In the circuit board with built-in electronic components of the presentinvention, it is preferable that the insulating layer in the circuitboard is formed of a mixture including an inorganic filler and athermosetting resin, and it is more preferable that the mixture includesthe inorganic filler in an amount of 70 wt % or more and 95 wt % orless. This is because the heat produced by the electronic components canbe dissipated speedily by the inorganic filler, and therefore a circuitboard with built-in electronic components of high reliability can beobtained. Furthermore, it is preferable that the thermosetting resincontains at least one resin selected from the group consisting of epoxyresins, phenol resins, and isocyanate resins. This is because the curedproducts resulting from these resins have superior heat resistance andelectrical insulation properties. Furthermore, it is preferable that theinorganic filler contains at least one type of substance selected fromthe group consisting of Al₂O₃, MgO, BN, AlN, and SiO₂. This is becausethese materials have superior heat dissipation properties. Furthermore,the coefficient of linear expansion of the circuit board with built-inelectronic components can be increased when MgO is used as the inorganicfiller. Furthermore, the dielectric constant of the circuit board withbuilt-in electronic components can be reduced when SiO₂ (in particular,amorphous SiO₂) is used as the inorganic filler. Furthermore, thecoefficient of linear expansion of the circuit board with built-inelectronic components can be lowered when BN is used as the inorganicfiller.

In the circuit board with built-in electronic components of the presentinvention, it is preferable that an inner via through which the firstwiring pattern and the second wiring pattern can be mutuallyelectrically connected further is provided. In this manner it ispossible to further increase the containment rate of wiring.Furthermore, it is preferable that the inner via is formed of anelectroconductive resin composition, as this can be manufacturedreadily.

In the circuit board with built-in electronic components of the presentinvention, a semiconductor chip may be used as the electronic component,and it is possible to use a configuration that is formed by laminatingat least two semiconductor chips with an adhesive. Furthermore, for theelectronic component, it is possible to use a configuration in which atleast two semiconductor chips are mounted on a flexible substrate, andthe substrate is bent so that orientations that the external connectionterminals of the at least two semiconductor chips face are differentfrom each other.

It is preferable that the circuit board with built-in electroniccomponents of the present invention further includes at least onepassive component selected from the group consisting of a chip-formresistor, a chip-form capacitor, and a chip-form inductor, and that thepassive component is positioned inside the insulating layer. This isbecause it is possible to achieve a circuit board with built-inelectronic components having a desired functionality by including apassive component.

Furthermore, the circuit board with built-in electronic components ofthe present invention easily can be produced with first and secondmanufacturing methods of a circuit board with built-in electroniccomponents of the present invention.

In the step (a) of the first and second manufacturing methods of acircuit board with built-in electronic components of the presentinvention, it is possible to arrange a connection member on the secondexternal connection terminal of the electronic component.

In the step (b) of the first method for manufacturing a circuit boardwith built-in electronic components of the present invention, it is alsopossible to form a connection member in a predetermined area on thesecond electroconductive body, and superpose the secondelectroconductive body on the sheet-form material with the connectionmember in a direction facing the sheet-form material.

In the step (b) of the second method for manufacturing a circuit boardwith built-in electronic components of the present invention, it is alsopossible to form a connection member in a predetermined area of thesecond wiring pattern, and superpose the second wiring pattern that isformed on a support member on the sheet-form material with theconnection member in a direction facing the sheet-form material.Furthermore, after a step (c) in the second method for manufacturing acircuit board with built-in electronic components of the presentinvention, it is possible to include a further step in which only thesupport member is peeled from the layered structure.

In first and second manufacturing methods of a circuit board withbuilt-in electronic components of the present invention, the connectionmembers can be formed from at least one selected from solders,electroconductive resin compositions, anisotropic conductive sheets, andprojection electrodes, and furthermore it is possible to form theconnection members by layering a projection electrode and an anisotropicconductive sheet or an electroconductive resin composition.

In first and second manufacturing methods of a circuit board withbuilt-in electronic components of the present invention, it ispreferable that the mixture contains an inorganic filler in an amount of70 wt % or more and 95 wt % or less.

Hereinafter, embodiments of the present invention will be described withreference to the accompanying drawings.

FIRST EMBODIMENT

FIG. 1 is a cross-sectional view showing one embodiment of a circuitboard with built-in electronic components of the present invention. Acircuit board 1 with built-in electronic components of this embodimentincludes an insulating layer 11, a first wiring pattern 12 formed on onemain surface (a first main surface) of the insulating layer 11, a secondwiring pattern 13 formed on another main surface (a second main surface)of the insulating layer 11, an inner via 14 for electrically connectingthe first wiring pattern 12 and the second wiring pattern 13, andsemiconductor chips (electronic components) 15 a and 15 b embedded inthe insulating layer 11. An external connection terminal (first externalconnection terminal) 16 is provided on the semiconductor chip 15 a on asurface (a first surface) that faces the first wiring pattern 12, and anexternal connection terminal 18 is provided on a surface (a secondsurface) that faces the second wiring pattern 13. The externalconnection terminal 16 is connected electrically to the first wiringpattern 12 via a connection member 17. The external connection terminal(second external connection terminal) 18 is connected electrically tothe second wiring pattern 13 via a connection member 19. Thesemiconductor chip 15 b is connected electrically to the first wiringpattern 12.

Any material having electrical insulation properties can be used for theinsulating layer 11, but it is preferable that it is formed with acomposite material containing an inorganic filler and a thermosettingresin. This is because the heat produced from the semiconductor chips 15a and 15 b is dissipated more easily by the inorganic filler containedin the insulating layer 11, and also because factors such as the thermalconductivity and dielectric constant of the insulating layer 11 can becontrolled in accordance with the built-in electronic component byselecting the material of the inorganic filler as appropriate. It ispreferable that the inorganic filler includes at least one selected fromAl₂O₃, MgO, BN, AlN, and SiO₂. This is because these materials havesuperior thermal conductivity, and therefore can increase the thermaldissipation properties of the insulating layer 11. It is preferable thatthe thermosetting resin includes at least one selected from, forexample, epoxy resins, phenol resins, and isocyanate resins. This isbecause the cured products resulting from these thermosetting resinshave superior electric insulation, mechanical strength, and heatresistance.

There is no particular limitation regarding the material of the firstand second wiring patterns 12 and 13, as long as the material has goodelectric conductivity and can facilitate circuit patterning, but metalfoil is preferable. For example, copper, nickel, aluminum, and alloysincluding any of these metals as a main component can be used for themetal foil, and copper or an alloy with copper as a main component ispreferable in particular. This is because copper has superior electricalconductivity, is inexpensive, and facilitates wiring pattern formations.

It is preferable that the inner via 14 is formed from anelectroconductive resin composition in which an electroconductivematerial and a thermosetting resin are mixed. It is preferable thatpowered gold, silver, or copper or the like is used as theelectroconductive material, but copper in particular is preferable sinceit has excellent electroconductive properties with little migration, andmoreover is inexpensive. Furthermore, it is possible to inhibitincreased resistance due to copper oxidation by using a powder in whicha silver coating is given to copper particles. It is preferable that thesame resin as the thermosetting resin used in forming the insulatinglayer 11 is used for the thermosetting resin, and liquid epoxy resinsare preferable because they are stable in terms of the heat resistanceproperties.

At least one selected from solders, electroconductive resincompositions, and anisotropic conductive sheets suitably can be used forthe connection members 17 and 19. Furthermore, it is also possible touse a projection electrode formed of at least one metal selected fromthe group consisting of gold, silver, copper, platinum, solder, andaluminum, or an alloy including at least one of these metals. Moreover,a projection electrode coated with an electroconductive resincomposition, or a combination of a projection electrode and ananisotropic conductive sheet also can be used suitably. For example, amixture of gold, silver, copper, or a silver-palladium alloy or the likeand a thermosetting resin can be used here for the electroconductiveresin compositions.

The semiconductor chip 15 a is provided with external connectionterminals 16 and 18 that are, for example, aluminum electrodes on twodifferent surfaces. By providing the external connection terminals ontwo surfaces in this manner, reductions in the containment rate ofwiring can be inhibited to achieve high density even when connecting asemiconductor chip 15 a respectively to the first wiring pattern 12 andthe second wiring pattern 13 formed on different surfaces of theinsulating layer 11. Moreover, since both the first wiring pattern 12and the second wiring pattern 13 can be used, the design rules for theexternal connection terminals of the semiconductor chip 15 a can beeased, and miniaturization of the semiconductor 15 a can be achieved.

Next, a first example of a method for manufacturing a circuit board 1with built-in electronic components of this embodiment will be describedwith reference to FIGS. 2A to 2F.

First, a sheet-form material 101 is produced by processing a mixture ofan inorganic filler and an uncured thermosetting resin into a sheet form(see FIG. 2A). Specifically, a paste-like kneaded material is formed bymixing an inorganic filler and a liquid thermosetting resin, orsimilarly a paste-like kneaded material is formed by mixing an inorganicfiller and thermosetting resin that has been given low viscosity by asolvent, then a sheet-form material 101 is obtained by molding thispaste-like kneaded material into a shape with uniform thickness andperforming heat treatment. A reason for performing heat treatment isthat there is viscosity when a liquid resin is used, so that byproceeding with curing to a certain extent by heat treatment, it ispossible to achieve a sheet-form material 101 in which adhesiveness isremoved while maintaining the flexibility of an uncured state.Furthermore, when a kneaded material in which a resin has been dissolvedby a solvent is used, heat treatment is performed to remove the solventand similarly remove the adhesiveness while maintaining the flexibilityof an uncured state.

Next, a pass-through opening 102 is formed in a predetermined area ofthe sheet-form material 101, which is in an uncured state (see FIG. 2B).The forming of the pass-through opening 102 can be achieved byprocessing using a laser processing method, or a mold, or by a punchingprocess. In particular, with a laser processing method, it is effectiveto use a carbon dioxide gas laser, an excimer laser, or a YAG laser.This is because these have fast processing speeds.

Next, the inside of the pass-through opening 102 is filled with anelectroconductive resin composition 103 (see FIG. 2C). Theelectroconductive resin composition 103 becomes an inner via 14 (seeFIG. 1) via a later thermal curing process. It is also possible toobtain the sheet-form material 101 with the electroconductive resincomposition 103 indicated by FIG. 2C, by attaching a mold release filmformed of PET (polyethylene terephthalate) or PPS (polyphenylenesulfide) on the sheet-form material 101, forming the pass-throughopening 102 and filling the inside of the pass-through opening 102 withthe electroconductive resin composition 103.

Next, an electronic component-mounted structure on which semiconductorchips 105 a and 105 b are mounted on a first electroconductive body 104of copper foil or the like, and a second electroconductive body 110 ofcopper foil or the like, which are manufactured in a separate process,are prepared. The electronic component-mounted structure and the secondelectroconductive body 110 are positioned and superposed on the top andbottom surfaces of sheet-form material 101 shown in FIG. 2C (see FIG.2D). At this time, a gap may be provided, if necessary, in thesheet-form material 101. On the semiconductor chip 105 a, an externalconnection terminal 108 also is provided on a surface (second surface)on the opposite side of the mounting surface (first surface) on which anexternal connection terminal 106 connected to the firstelectroconductive body 104 is provided. Here, a connection member 109 isprovided on the external connection terminal 108 that is provided on thesurface on the opposite side of the mounting surface, but this may beprovided prior to the semiconductor chip 105 a being mounted on thefirst electroconductive body 104, or may be formed after mounting. It ispossible to form the connection member 109 using methods including, forexample, a plating method in which a solder is formed, a dispensingmethod or a screen printing method in which an electroconductive resincomposition is applied, or a method of attaching an anisotropicconductive sheet. A mixture obtained by kneading gold, silver, copper,or a silver-palladium alloy or the like with a thermosetting resin canbe used here as the electroconductive resin composition. Moreover, theconnection member 107 used in connecting the external connectionterminal 106 and the first electroconductive body 104 may be formedsimilarly. It should be noted that the semiconductor chip 105 bsimilarly is connected to the first electroconductive body 104.Furthermore, it is preferable that the adhesion surfaces of the firstelectroconductive body 104 and the second electroconductive body 110with the sheet-form material 101 are roughened to improve the adhesionto the sheet-form material 101. Furthermore, it is preferable that acoupling process, or a tin, zinc, or nickel plating is implemented onthe surfaces of the first electroconductive body 104 and the secondelectroconductive body 110 similarly to improve adhesion and to preventoxidation. Furthermore, it is also possible inject a sealing resinbetween the first electroconductive body 104 and the semiconductor chips105 a and 105 b. By doing this, it is possible to adhere thesemiconductor chips 105 a and 105 b to the first electroconductive body104 firmly.

Next, the layered structure in which the sheet-form material 101, theelectronic component-mounted structure, and the second electroconductivebody 110 are positioned and superposed is pressed in the layereddirection by a pressing device and further heated, so that thesemiconductor chips 105 a and 105 b are embedded in the sheet-formmaterial 101 and the connection member 109 and the secondelectroconductive body 110 are adhered together so that the wholebecomes integrated (see FIG. 2E). At this time, the semiconductor chips105 a and 105 b are embedded in the sheet-form material 101 before thethermosetting resin contained in the sheet-form material 101 is cured,and then a heating process is performed, so that the thermosetting resinof the sheet-form material 101 and the thermosetting resin of theelectroconductive resin composition 103 are cured. In this manner, thesheet-form material 101, the semiconductor chips 105 a and 105 b, andthe first and second electroconductive bodies 104 and 110 are mutuallyadhered in a mechanically firm manner. Moreover, the firstelectroconductive body 104 and the second electroconductive body 110become electrically connected via the inner via formed by the curing ofthe electroconductive resin composition 103, and the external connectionterminal 108 and the second electroconductive body 110 becomeelectrically connected and fixed via the connection member 109.

Next, the first and second electroconductive bodies 104 and 110 arepatterned using an existing photolithography process to form a firstwiring pattern 12 and a second wiring pattern 13. In this manner, it ispossible to manufacture the circuit board 1 with built-in electroniccomponents of this embodiment (see FIG. 2F). After this, other processesare performed as appropriate, such as mounting other components usingsoldering and filling insulating resins, but the description of suchprocesses is omitted here.

FIGS. 3A to 3F are cross-sectional views showing the steps in a secondexample of a method for manufacturing the circuit board 1 with built-inelectronic components. Apart from a difference in the structure of theelectronic component-mounted structure, the method for manufacturing thesecond example is the same as the method for manufacturing the firstexample, and therefore duplicated description is omitted here.

The steps (see FIGS. 3A to 3C) in which the sheet-form material 101filled with the electroconductive resin composition 103 is manufacturedare the same as in the first example.

Following this, an electronic component-mounted structure on which thesemiconductor chips 105 a and 105 b are mounted on the firstelectroconductive body 104 and the second electroconductive body 110,which are manufactured separately, are prepared. The electroniccomponent-mounted structure and the second electroconductive body 110are positioned and superposed on the top and bottom surfaces of thesheet-form material 101 shown in FIG. 3C (see FIG. 3D). At this time, agap may be provided, if necessary, in the sheet-form material 101.Unlike in the first example, the electronic component-mounted structureused here has a projection electrode 111 formed on the externalconnection terminal 108 that is provided on the surface on the oppositeside of the mounting surface of the semiconductor chip 105 a. Theprojection electrode 111 becomes connection member 19 (see FIG. 1) via alater process. It should be noted that the structure of the electroniccomponent-mounted structure here is otherwise the same as in the firstexample. The projection electrode 111 can be formed using wiring such asgold and aluminum or the like in equipment such as a bump bonder, andcan also be formed by applying and curing an electroconductive resincomposition.

Subsequent steps (see FIGS. 3E and 3F) are the same as in the firstexample.

In the case of the second example, the reliability of the electricalconnection can be increased by using the projection electrode 111 in theconnection of the external connection terminal 108 of the semiconductorchip 105 a to the second electroconductive body 110.

FIGS. 4A to 4F are cross-sectional views showing the steps in a thirdexample of a method for manufacturing the circuit board 1 with built-inelectronic components. Apart from a difference in the structure of theelectronic component-mounted structure, the method for manufacturing thethird example is the same as the method for manufacturing the firstexample described with reference to FIGS. 2A to 2F, and thereforeduplicated description is omitted here.

The steps (see FIGS. 4A to 4C) in which the sheet-form material 101filled with the electroconductive resin composition 103 is manufacturedare the same as in the first example.

Following this, an electronic component-mounted structure on which thesemiconductor chips 105 a and 105 b are mounted on the firstelectroconductive body 104 and the second electroconductive body 110,which are manufactured separately, are prepared. The electroniccomponent-mounted structure and the second electroconductive body 110are positioned and superposed on the top and bottom surfaces of thesheet-form material 101 shown in FIG. 4C (see FIG. 4D). At this time, agap may be provided, if necessary, in the sheet-form material 101.Unlike in the first and second examples, the electroniccomponent-mounted structure used here has a projection electrode 111formed on the external connection terminal 108 that is provided on thesurface on the opposite side of the mounting surface of thesemiconductor chip 105 a as well as a further electroconductive resincomposition 112 applied to the projection electrode 111. It should benoted that the structure of the electronic component-mounted structurehere is otherwise the same as in the first example. The projectionelectrode 111 can be formed with a same method as described in regard tothe second example. A mixture obtaining by kneading gold, silver,copper, platinum, solder, or a silver-palladium alloy or the like with athermosetting resin can be used here as the electroconductive resincomposition 112, which can be formed using a method such as applying anelectroconductive resin composition onto the projection electrode 111using a dispensing method or a method in which an electroconductiveresin composition is scrapped with the projection electrode 111.

Subsequent steps (see FIGS. 4E and 4F) are the same as in the firstexample.

In the case of the third example, the reliability of the electricalconnection can be increased further by using the layered structure ofthe projection electrode 111 and the electroconductive resin composition112 as the connection member 19.

SECOND EMBODIMENT

FIG. 5 is a cross section of another embodiment of a circuit board withbuilt-in electronic components of the present invention. Apart from thestructure of the electrical connection portion of the semiconductor chip15 a and the second wiring pattern 13, a circuit board 2 with built-inelectronic components of this embodiment is the same as the circuitboard 1 with built-in electronic components described in the firstembodiment, and therefore description of components with the samereference numbers is omitted here.

In the circuit board 2 with built-in electronic components of thisembodiment, the external connection terminal 18 of the semiconductorchip 105 a is connected to the second wiring pattern 13 via a connectionmember 19 and an anisotropic conductive sheet 20. The anisotropicconductive sheet 20 is positioned between a predetermined area of thesecond wiring pattern 13 and the insulating layer 11. In this manner,the reliability of the connection of the external connection terminal 18and the second wiring pattern 13 can be made even higher.

Next, an example method for manufacturing the circuit board 2 withbuilt-in electronic components is described with reference to FIGS. 6Ato 6F. Apart from differences in the second electroconductive body 110,the method for manufacturing the circuit board 2 with built-inelectronic components of this embodiment is the same as the methoddescribed in the first embodiment (the method described with referenceto FIGS. 3A to 3F), and therefore duplicated description is omittedhere.

The steps (see FIGS. 6A to 6C) in which the sheet-form material 101filled with the electroconductive resin composition 103 is manufacturedare the same as in the first embodiment.

Following this, an electronic component-mounted structure on which thesemiconductor chips 105 a and 105 b are mounted on the firstelectroconductive body 104 and the second electroconductive body 110,which are manufactured separately, are prepared. The electroniccomponent-mounted structure and the second electroconductive body 110are positioned and superposed on the top and bottom surfaces of thesheet-form material 101 shown in FIG. 6C (see FIG. 6D). At this time, agap may be provided, if necessary, in the sheet-form material 101. Theelectronic component-mounted structure used here has the projectionelectrode 111 formed on the external connection terminal 108 that isprovided on a surface of an opposite side to the mounting surface of thesemiconductor chip 105 a. The method of forming the projection electrode111 is the same as described for the first embodiment. On the otherhand, an anisotropic conductive sheet 113 is attached to the secondelectroconductive body 110 in an area facing the semiconductor chip 105a.

Subsequent steps (see FIGS. 6E and 6F) are the same as in the firstembodiment.

With the above-described manufacturing method, a circuit board 2 withbuilt-in electronic components that has higher connection reliabilitycan be manufactured by attaching the anisotropic conductive sheet 113 tothe second electroconductive body 110 in advance.

THIRD EMBODIMENT

FIG. 7 is a cross section of another embodiment of a circuit board withbuilt-in electronic components of the present invention. Apart frombeing provided with a through-hole 21 rather than an inner via toelectrically connect the first wiring pattern 12 and the second wiringpattern 13, a circuit board 3 with built-in electronic components ofthis embodiment is the same as the circuit board 1 with built-inelectronic components described in the first embodiment. After thesemiconductor chip 15 a is embedded in the insulating layer 11 andintegrated as a whole, the through-hole 21 is formed by performing ahole-machining such as drilling or laser processing, then furtherperforming a plating process.

With the circuit board 3 with built-in electronic components, it is alsopossible to obtain the same effect as the circuit boards 1 and 2 withbuilt-in electronic components.

FOURTH EMBODIMENT

FIG. 8 is a cross section of another embodiment of a circuit board withbuilt-in electronic components of the present invention. Apart from thefirst wiring pattern 12 and the second wiring pattern 13 being embeddedand positioned in the insulating layer 11, a circuit board 4 withbuilt-in electronic components of this embodiment is the same as thecircuit board 1 with built-in electronic components described in thefirst embodiment. With the circuit board 4 with built-in electroniccomponents, in addition to the effect obtainable with the circuit board1 with built-in electronic components of the first embodiment, it isalso possible to obtain an effect such that the surface of the board ismade smooth so that the subsequent mounting properties are superior.

Next, a first example of a method for manufacturing the circuit board 4with built-in electronic components is described with reference to FIGS.9A to 9F.

The steps (see FIGS. 9A to 9C) in which the sheet-form material 101filled with the electroconductive resin composition 103 is manufacturedare the same as in the first embodiment.

Following this, an electronic component-mounted structure on which thesemiconductor chips 105 a and 105 b are mounted on a first wiringpattern 115 formed on a mold release film (support member) 114, and asecond wiring pattern 117 formed on a mold release film (support member)116, which are manufactured separately, are prepared. The electroniccomponent-mounted structure and the mold release film 116 on which thesecond wiring pattern 117 is formed are positioned and superposed on thetop and bottom surfaces of the sheet-form material 101 shown in FIG. 9C(see FIG. 9D). At this time, a gap may be provided, if necessary, in thesheet-form material 101. In the electronic component-mounted structureused here, the first wiring pattern 115 can be formed by forming aelectroconductive body film of copper foil or the like on the moldrelease film 114, and patterning this electroconductive body film in apredetermined shape using an ordinary photolithography process. Theelectronic component-mounted structure is formed by mounting thesemiconductor chips 105 a and 105 b on the first wiring pattern 115.Furthermore, the connection member 109 is provided on the externalconnection terminal 108 that is provided on the surface on the oppositeside of the mounting surface of the semiconductor chip 105 a.Furthermore, the second wiring pattern 117 that is formed on the moldrelease film 116 also can be formed by the same method as the firstwiring pattern 115. Film made of polyethylene terephthalate, forexample, can be used for the mold release films 114 and 116. It is alsopossible to use metal peelable clad foils instead of the mold releasefilms 114 and 116.

Next, the layered structure in which the following are positioned andsuperposed: the sheet-form material 101; the electroniccomponent-mounted structure (in which the first wiring pattern 115 isformed on the mold release film 114 and the semiconductor chips 105 aand 105 b are mounted thereon); and the mold release film 116 on whichthe second wiring pattern 117 is formed; is pressed in the layereddirection by a pressing device and further heated. With this step, thesemiconductor chips 105 a and 105 b are embedded in the sheet-formmaterial 101 and the connection member 109 formed on the externalconnection terminal 108 of the semiconductor chip 105 a and the secondwiring pattern 117 are brought into contact so that the whole becomesintegrated (see FIG. 9E). This step is substantially the same as in thefirst embodiment.

Next, only the mold release films 114 and 116 are peeled from theintegrated layered structure. In this manner, the circuit board 4 withbuilt-in electronic components can be manufactured (see FIG. 9F).

FIGS. 10A to 10F are cross-sectional views showing the steps in a secondexample of a method for manufacturing the circuit board 4 with built-inelectronic components.

The steps (see FIGS. 10A to 10C) in which the sheet-form material 101filled with the electroconductive resin composition 103 is manufacturedare the same as in the first embodiment.

Following this, an electronic component-mounted structure on which thesemiconductor chips 105 a and 105 b are mounted on the first wiringpattern 115 formed on the mold release film 114, and the second wiringpattern 117 formed on the mold release film 116, which are manufacturedseparately, are prepared. The electronic component-mounted structure andthe mold release film 116 on which the second wiring pattern 117 isformed are positioned and superposed on the top and bottom surfaces ofthe sheet-form material 101 shown in FIG. 10C (see FIG. 10D). At thistime, a gap may be provided, if necessary, in the sheet-form material101. The electronic component-mounted structure used here is notprovided with a connection member on the external connection terminal108 of the mounted semiconductor chip 105 a, but the rest of itsstructure is the same as in the first example. On the other hand, aconnection member 109 is provided in a predetermined position (aposition corresponding to the external connection terminal 108 of themounted semiconductor chip 105 a) on the second wiring pattern 117formed on the mold release film 116. Exemplary methods of forming theconnection member 109 include a method such as applying anelectroconductive resin composition using a dispensing method or ascreen printing method, or a method of attaching an anisotropicconductive sheet that has been processed into a desired shape.

Next, the layered structure in which the following are positioned andsuperposed: the sheet-form material 101; the electroniccomponent-mounted structure (in which the first wiring pattern 115 isformed on the mold release film 114, and the semiconductor chips 105 aand 105 b are mounted thereon); and the mold release film 116 on whichthe second wiring pattern 117 and the connection member 109 are formed;is pressed in the layered direction by a pressing device and furtherheated so that the semiconductor chips 105 a and 105 b are embedded inthe sheet-form material 101 and the external connection terminal 108 ofthe semiconductor chip 105 a and the connection member 109 are broughtinto contact to form an integrated whole (see FIG. 10E). This step issubstantially the same as in the first embodiment.

FIFTH EMBODIMENT

FIG. 11 is a cross section of another embodiment of a circuit board withbuilt-in electronic components of the present invention. A circuit board5 with built-in electronic components of this embodiment is formed withother circuit boards 22 and 23 layered on the top and bottom surfaces ofthe circuit board 1 with built-in electronic components shown in FIG. 1.With the circuit board 5 with built-in electronic components, thecontainment rate of wiring can be increased even more than the circuitboard 1 with built-in electronic components and packaging density can beincreased since the circuit boards 22 and 23 are further provided.Flexible substrates, resin substrates, ceramic substrates, double-facedcircuit boards, multi-layer circuit boards, and circuit boards withbuilt-in electronic components can be used suitably for the circuitboards 22 and 23. It should be noted that the circuit boards 22 and 23are provided on both surfaces of the insulating layer 11 in the circuitboard 5 with built-in electronic components of this embodiment, but alsocan be provided on only one surface. As one example of the circuit board5 with built-in electronic components, a configuration is conceivable inwhich the circuit board 23 is provided on only one surface of theinsulating layer 11, similar to as shown in FIG. 21. In this example,the circuit board 23 is formed with a semiconductor chip 234 built in aninsulating layer 231, and an external connection terminal 235 of thesemiconductor chip 234 is electrically connected to a wiring pattern 232of the circuit board 23 via a connection member 236. Furthermore, thewiring pattern 232 of the circuit board 23 is connected electrically tothe first wiring pattern 12 via an inner via 233.

FIGS. 12A to 12E are cross-sectional views showing the steps in anexample method for manufacturing the circuit board 5 with built-inelectronic components shown in FIG. 11.

The steps (see FIGS. 12A to 12C) in which the sheet-form material 101filled with the electroconductive resin composition 103 is manufacturedare the same as in the first embodiment.

Following this, an electronic component-mounted structure on which thesemiconductor chips 105 a and 105 b are mounted on the first wiringpattern 119 formed on the circuit board 118, and the second wiringpattern 121 formed on the circuit board 120, which are manufacturedseparately, are prepared. It should be noted that the circuit boards 118and 120 function as support members in this embodiment. The electroniccomponent-mounted structure and the circuit board 120 on which thesecond wiring pattern 121 is formed are positioned and superposed on thetop and bottom surfaces of the sheet-form material 101 shown in FIG. 12C(see FIG. 12D). At this time, a gap may be provided, if necessary, inthe sheet-form material 101. A connection member 109 is provided on theexternal connection terminal 108 provided on the surface on the oppositeside of the mounting surface of the semiconductor chip 105 a. A sealingresin may be injected between the circuit board 118 and thesemiconductor chip 105 a in the electronic component-mounted structure.By doing this, it is possible to adhere the first wiring pattern 119 andthe semiconductor chip 105 a firmly.

Next, the layered structure in which the following are positioned andsuperposed: the sheet-form material 101; the electroniccomponent-mounted structure (in which the first wiring pattern 119 isformed on the circuit board 118, and the semiconductor chips 105 a and105 b are mounted thereon); and the mold release film 120 on which isformed the second wiring pattern 121; is pressed in the layereddirection by a pressing device and further heated so that thesemiconductor chips 105 a and 105 b, as well as the first wiring pattern119 and the second wiring pattern 121, are embedded in the sheet-formmaterial 101 and the connection member 109 formed on the externalconnection terminal 108 of the semiconductor chip 105 a and the secondwiring pattern 121 are brought into contact to form an integrated whole.This step is substantially the same as in the first embodiment. At thistime, the circuit boards 118 and 120 are adhered to the insulating layer101 in a mechanically firm manner. Through this process, the circuitboard 5 with built-in electronic components is completed (see FIG. 12E).

SIXTH EMBODIMENT

FIG. 13 is a cross section of another embodiment of a circuit board withbuilt-in electronic components of the present invention. Apart from adifferent structure of the built-in semiconductor chips, a circuit board6 with built-in electronic components of this embodiment is the same asthe circuit board 5 with built-in electronic components of the fifthembodiment. In the built-in semiconductor chips 24 in this embodiment,two semiconductor chips 24 a and 24 b are attached to each other with anadhesive 24 c such that their surfaces on which there are no externalconnection terminals are opposed to each other. The same effect as thecircuit board 5 with built-in electronic components of the fifthembodiment can be obtained with the circuit board 6 with built-inelectronic components.

FIGS. 14A to 14E are cross-sectional views showing the steps in anexample method for manufacturing the circuit board 6 with built-inelectronic components shown in FIG. 13.

The steps (see FIGS. 14A to 14C) in which the sheet-form material 101filled with the electroconductive resin composition 103 is manufacturedare the same as in the first embodiment.

Following this, an electronic component-mounted structure on whichsemiconductor chips 204 a and 105 b are mounted on the first wiringpattern 119 formed on the circuit board 118, and an electroniccomponent-mounted structure on which a semiconductor chip 204 b ismounted on the second wiring pattern 121 formed on the circuit board120, which are manufactured separately, are prepared. An externalconnection terminal 106 of the semiconductor chip 204 a is connected tothe first wiring pattern 119 via a connection member 107. An externalconnection terminal 108 of the semiconductor chip 204 b is connected tothe second wiring pattern 121 via a connection member 109. An adhesive204 c is applied to the surface of the semiconductor chip 204 b. In theelectronic component-mounted structure, a sealing resin may be injectedbetween the circuit board 118 and the semiconductor chip 204 a, andbetween the circuit board 120 and the semiconductor chip 204 b. By doingthis, it is possible to adhere firmly the first wiring pattern 119 andthe semiconductor chip 204 a, and the second wiring pattern 121 and thesemiconductor chip 204 b respectively. The electronic component-mountedstructure on which the semiconductor chips 204 a and 105 b are mounted,and the electronic component-mounted structure on which thesemiconductor chip 204 b is mounted are positioned and superposed on thetop and bottom surfaces of the sheet-form material 101 shown in FIG. 14C(see FIG. 14D). At this time, a gap may be provided, if necessary, inthe sheet-form material 101. In this case, the electroniccomponent-mounted structures can be positioned such that thesemiconductor chip 204 a and the semiconductor chip 204 b are opposed toeach other.

Next, the layered structure in which the sheet-form material 101 and thetwo electronic component-mounted structures (the structure in which thesemiconductor chips 204 a and 105 b are mounted on the circuit board118, and the structure in which the semiconductor chip 204 b is mountedon the circuit board 120) are positioned and superposed is pressed inthe layered direction by a pressing device and further heated. In thismanner, the semiconductor chips 204 a and 105 b, the first wiringpattern 119, the semiconductor chip 204 b, and the second wiring pattern121 are embedded in the sheet-form material 101 to form an integratedwhole. At this time, the semiconductor chip 204 a and the semiconductorchip 204 b are attached with the adhesive 204 c. The circuit boards 118and 120 are adhered to the insulating layer 101 in a mechanically firmmanner. Through this process, the circuit board 6 with built-inelectronic components is completed (see FIG. 14E).

It should be noted that, in the example manufacturing method shown inFIGS. 14A to 14E, the semiconductor chips 204 a and 204 b are attachedto each other after the semiconductor chips 204 a and 204 b have beenmounted respectively on the circuit boards 118 and 120, but it is alsoof course possible to apply a manufacturing method described in theembodiments 1 to 5 by using a configuration in which the semiconductorchips 204 a and 204 b are attached to each other in advance.

Furthermore, in the configuration example shown in FIG. 13, the twosame-size semiconductor chips 24 a and 24 b are attached without anydisplacement, but it is also possible to attach the two semiconductorchips 24 a and 24 b with a displacement as in the configuration exampleshown in FIG. 15. Moreover, rather than semiconductor chips of the samesize, it is possible to attach two semiconductor chips 24 a and 24 b ofdifferent sizes as in the configuration example shown in FIG. 16.Furthermore, the semiconductor chips to be attached also may havedifferent thicknesses.

Further still, the number of semiconductor chips to be attached to eachother is not limited to two, but may be three or more. For example, asshown in FIG. 17, a semiconductor chip 25 is possible in which threesemiconductor chips 25 a to 25 c are attached together with an adhesive25 d.

Furthermore, the structure of the electronic components formed byattaching a plurality of semiconductor chips is not limited by the abovedescription and, for example, it is possible to use a configuration suchas that shown in FIG. 18 in which external connection terminals 33 a and33 b of a plurality of semiconductor chips 32 a and 32 b arerespectively joined to a flexible substrate 35 such as a resin film byconnection members 36 a and 36 b, and the substrate 35 is bent such thatthe external connection terminals 33 a and 33 b of the semiconductorchips 32 a and 32 b face opposite directions. It should be noted that anelectroconductive material such as a solder for example can be used forthe connection members 36 a and 36 b. A wiring pattern 37 is provided onthe surface on the opposite side of the surface on which the connectionmembers 36 a and 36 b are provided on the substrate 35 and, although notparticularly evident in the drawings, the connection members 36 a and 36b and the wiring pattern 37 are electrically connected inside thesubstrate 35. It should be noted that an example is shown in FIG. 18 inwhich the substrate 35 is bent such that the external connectionterminals 33 a and 33 b of the semiconductor chips 32 a and 32 b faceopposite sides, but there is no limitation to this and it is alsopossible to use a configuration in which the substrate 35 is bent suchthat the external connection terminals 33 a and 33 b face differentorientations from each other.

SEVENTH EMBODIMENT

FIG. 19A is a cross section showing another embodiment of a electroniccomponent-mounted structure of the present invention. Apart fromdifferences in the structure of the mounted semiconductor chips and themounting method thereof, a circuit board 7 with built-in electroniccomponents of this embodiment is the same as the circuit board 6 withbuilt-in electronic components of the sixth embodiment. A semiconductorchip 28 mounted in this embodiment is formed by attaching twosemiconductor chips 28 a and 28 b with an adhesive 28 c. However, unlikein the case of the sixth embodiment, a surface on which the externalconnection terminal 29 of the semiconductor chip 28 a is provided and asurface on which the external connection terminal 18 of thesemiconductor chip 28 b is not provided are attached with the adhesive28 c, and the external connection terminal 29 of the semiconductor chip28 a is electrically connected to the first wiring pattern 12 with awiring 30. The semiconductor chip 28 a is attached to the circuit board23 with an adhesive 31. Furthermore, the two semiconductor chips to beattached may both be mounted with wire bonding and, as shown in FIG. 19Bfor example, the external connection terminals 29 a and 29 b of thesemiconductor chips 28 a and 28 b may also be electrically connectedrespectively to the first wiring pattern 12 and the second wiringpattern 13 using wirings 30 a and 30 b. In this case, the twosemiconductor chips 28 a and 28 b are attached using the adhesive 28 c,but it is preferable that a spacer 28 d is provided between these sothat their respective wirings 30 a and 30 b do not come into contact.Furthermore, the semiconductor chips 28 a and 28 b are respectivelyattached to the circuit boards 23 and 22 using the adhesives 31 a and 31b, which is the same as in FIG. 19A.

FIGS. 20A to 20E are cross-sectional views showing the steps in anexample method for manufacturing the circuit board 7 with built-inelectronic components shown in FIG. 19A. It should be noted that anexample of a method for manufacturing the circuit board 7 with built-inelectronic components shown in FIG. 19A is described here, but it isalso possible to manufacture the structure of the circuit board withbuilt-in electronic components shown in FIG. 19B using the same method.

The steps (see FIGS. 20A to 20C) in which the sheet-form material 101filled with the electroconductive resin composition 103 is manufacturedare the same as in the first embodiment.

Following this, an electronic component-mounted structure on whichsemiconductor chips 208 a and 105 b are mounted on the circuit board 118is prepared. In this electronic component-mounted structure, thesemiconductor chip 208 a is attached to the circuit board 118 with anadhesive 301 in such a manner that the surface on which the externalconnection terminal 209 is not provided is opposed to the circuit board118. The external connection terminal 209 is electrically connected witha wiring 300 to the first wiring pattern 119 formed on the circuit board118. Furthermore, as in the case of the sixth embodiment, thesemiconductor chip 105 b is mounted on the circuit board 119. Moreover,another electronic component-mounted structure on which a semiconductorchip 208 b is mounted on the second wiring pattern 121 formed on thecircuit board 120 is also prepared. The external connection terminal 108of the semiconductor chip 208 b is connected to the second wiringpattern 121 via a connection member 109. An adhesive 208 c is applied tothe surface of the semiconductor chip 208 b. The electroniccomponent-mounted structure on which the semiconductor chips 208 a and105 b are mounted, and the electronic component-mounted structure onwhich the semiconductor chip 208 b is mounted are positioned andsuperposed on the top and bottom surfaces of the sheet-form material 101shown in FIG. 20C (see FIG. 20D). At this time, a gap may be provided,if necessary, in the sheet-form material 101. In this case, theelectronic component-mounted structures can be positioned such that thesemiconductor chip 208 a and the semiconductor chip 208 b are opposed toeach other.

Next, the layered structure in which the following are positioned andsuperposed: the sheet-form material 101; the two electroniccomponent-mounted structures (on one of which the semiconductor chips208 a and 105 b are mounted on the circuit board 118, and on one ofwhich the semiconductor chip 208 b is mounted on the circuit board 120);is pressed in the layered direction by a pressing device and furtherheated. In this manner, the semiconductor chips 208 a and 105 b, thefirst wiring pattern 119, the semiconductor chip 208 b, and the secondwiring pattern 121 are embedded in the sheet-form material 101 to forman integrated whole. At this time, the semiconductor chip 208 a and thesemiconductor chip 208 b are attached using the adhesive 208 c. Thecircuit boards 118 and 120 become adhered to the insulating layer 101 ina mechanically firm manner. Through this process, the circuit board 7with built-in electronic components is completed (see FIG. 20E).

It should be noted that, in the example manufacturing method shown inFIGS. 20A to 20E, the semiconductor chips 208 a and 208 b are attachedafter the semiconductor chips 208 a and 208 b have been mountedrespectively on the circuit boards 118 and 120, but an equivalentembodiment of the circuit board with built-in electronic components alsocan be manufactured using a configuration in which the semiconductorchips 208 a and 208 b are attached to each other in advance.

EIGHTH EMBODIMENT

FIG. 22 is a cross section showing another embodiment of a circuit boardwith built-in electronic components of the present invention. In acircuit board 8 with built-in electronic components of this embodiment,the semiconductor chip 105 a to be built in is further provided with anexternal connection terminal 26 on a side surface thereof, and theexternal connection terminal 26 is electrically connected to the innervia 14 via the connection member 27. With the circuit board 8 withbuilt-in electronic components, in addition to the effect obtainablewith the circuit board 1 with built-in electronic components of thefirst embodiment, the containment rate of wiring can be increasedfurther and it is possible to achieve even further miniaturization ofthe semiconductor chip.

In the circuit boards 1 to 8 with built-in electronic components of theabove-described embodiments 1 to 8, it is also possible to use asemiconductor chip that has a bare chip or an insulating film such as apolyimide as a rewired layer as the semiconductor chip to be built in.

It should be noted that the circuit boards 1 to 8 with built-inelectronic components of the embodiments 1 to 8 are characterized inthat electronic components in which external connection terminals areprovided on different surfaces are built in, but when the electroniccomponent to be built in is formed from a single surface such as aspherical body for example, the same effect can be obtained by providingthe external connection terminals such that they face differentorientations.

Furthermore, in the circuit boards 1 to 8 with built-in electroniccomponents shown in the embodiments 1 to 8, since the externalconnection terminals provided on the semiconductor chips only have tofunction as electrodes, factors such as their shape are not limited inthe case of embodiments 1 to 8.

In the circuit boards 1 to 8 with built-in electronic components shownin the embodiments 1 to 8, only the semiconductor chips are built in,but other chip-form electronic components that are passive componentssuch as resistors, inductors, and capacitors may also be similarly builtin.

It should be noted that it is possible to combine and implement asdesired the configurations of the circuit boards 1 to 8 with built-inelectronic components shown in the embodiments 1 to 8.

The circuit boards with built-in electronic components and the methodsfor manufacturing these as described above are useful in achievinggreater density by increasing the containment rate of wiring in circuitboards with built-in electronic components in which electroniccomponents are built in.

The invention may be embodied in other forms without departing from thespirit or essential characteristics thereof The embodiments disclosed inthis application are to be considered in all respects as illustrativeand not limiting. The scope of the invention is indicated by theappended claims rather than by the foregoing description, and allchanges which come within the meaning and range of equivalency of theclaims are intended to be embraced therein.

1. A circuit board with a built-in electronic component comprising aninsulating layer, a first wiring pattern provided on a first mainsurface of the insulating layer, a second wiring pattern provided on asecond main surface different from the first main surface of theinsulating layer, and at least one electronic component provided in aninternal portion of the insulating layer; wherein the electroniccomponent comprises a first surface and a second surface that are twodifferent surfaces, a first external connection terminal formed on thefirst surface and a second external connection terminal formed on thesecond surface of the electronic component; wherein the first externalconnection terminal is connected electrically to the first wiringpattern, and the second external connection terminal is connectedelectrically to the second wiring pattern; and wherein the electroniccomponent is formed by attaching plural semiconductor chips to asemiconductor chip with an adhesive.
 2. The circuit board with abuilt-in electronic component according to claim 1, wherein the firstsurface is a surface facing the first wiring pattern in the electroniccomponent; and wherein the second surface is a surface facing the secondwiring pattern in the electronic component.
 3. The circuit board with abuilt-in electronic component according to claim 1, wherein theinsulating layer is formed of a mixture containing an inorganic fillerand a thermosetting resin.
 4. The circuit board with a built-inelectronic component according to claim 3, wherein the mixture containsthe inorganic filler in an amount of 70 wt % or more and 95 wt % orless.
 5. The circuit board with a built-in electronic componentaccording to claim 3, wherein the thermosetting resin contains at leastone resin selected from the group consisting of an epoxy resin, a phenolresin, and an isocyanate resin.
 6. The circuit board with a built-inelectronic component according to claim 3, wherein the inorganic fillercontains at least one selected from the group consisting of Al₂O₃, MgO,BN, AIN, and SiO₂.
 7. The circuit board with a built-in electroniccomponent according to claim 1, further comprising an inner via by whichthe first wiring pattern and the second wiring pattern are connectedelectrically.
 8. The circuit board with a built-in electronic componentaccording to claim 1, further comprising at least one passive componentselected from the group consisting of a chip-form resistor, a chip-formcapacitor, and a chip-form inductor, wherein the passive component ispositioned in an internal portion of the insulating layer.